The present invention is applicable to a vehicle height control system comprising a vehicle height adjuster for each of the wheels (a single adjuster may be provided for all of the rear wheels) for controlling the distance between each of the wheels and the vehicle body, that is, the vehicle body height, with each adjuster independently.
A vehicle height control system has been proposed heretofore, in which, in order to obtain a desired vehicle height in response to the number of passengers, the amount of loads, the travelling conditions and the road surface conditions, a plurality of vehicle height adjusters are employed to control the vehicle height at a target level.
In such a conventional vehicle height control system, when all the vehicle height adjusters are extended or contracted by the same length, the extension or contraction rate (the adjusting rate) would be different between the respective vehicle height adjusters due to the differences in the loads on or in the suspension spring characteristics of the respective vehicle height adjusters.
This variation in the adjusting rate causes an unstable slant of the vehicle body under adjustment and undesirably makes the driver and passengers (hereinafter simply called "the driver") feel uneasy.
This problem is attributable to the fact that each of the vehicle height adjusters is extended or contracted without regard to the adjusting rates of the other vehicle height adjusters.